Method of using a hydraulic power unit to control a mechanical jack

Abstract

A plurality of extendible jack stands are used in conjunction with, and their operation controlled by, a single power unit. The power unit transports an individual jack stand, positions it underneath a load, and raises or extends it. The jack stand is then locked in its extended position, and the power unit is detached from that jack stand and is then used for transporting, positioning, and raising another jack stand. When the load is to be lowered, the power unit controls the unlocking, lowering, and retraction of the jack stands, one at a time. In this manner a number of jack stands may be placed underneath a load, the load raised, the load later lowered, and the jack stands removed, without any need for the operator himself to place his body underneath the load.

What is claimed is: 
     
       1. A method of jacking up and supporting a vehicle or structure, comprising the steps of: selecting a plurality of jack stand units, each being capable of being vertically telescoped to an initial condition, of being vertically extended for raising a load, and of being locked in its vertically extended position;   selecting a machine that is capable of positioning and controlling a jack stand unit;   operating the machine so as to position the plurality of jack stand units, in their initial conditions, in corresponding fixed locations underneath the vehicle or structure;   operating the machine to control the units, one at a time, so that each unit is vertically extended and then locked, so as to raise and support the vehicle or structure; and   when it is desired to lower the vehicle or structure, operating the machine to control the units, one at a time, so that each unit is unlocked and then telescoped to its initial condition.   
     
     
       2. The method of accomplishing a remotely controlled jacking operation by means of hydraulic power while minimizing the problem of hydraulic bleed, comprising the steps of: selecting an extendible jack stand having a pair of elongated telescoping members, end plates carried by the respective members, ratchet means associated with the members, alignment means on one of the members, and ratchet release means associated with said alignment means;   positioning the plates of said jack stand so as to move a load when said jack stand is extended;   selecting a hydraulic power unit which includes a hydraulic cylinder and which is adapted to be aligned with and removably attached to said alignment means, and which also has a spaced pair of arms adapted for insertion between said plates, and control means for actuating said ratchet release means;   removably attaching said hydraulic power unit to said alignment means of said jack stand with said arms inserted between said plates;   then actuating said hydraulic cylinder so as to spread said arms and thereby cause said plates to move the load, said ratchet means then locking the members so that said plates continue to support the load;   removing said hydraulic power unit from said jack stand so that further use of said hydraulic cylinder in order to support the load is not required; and   when the jack stand is to be removed, re-attaching said hydraulic power unit to said jack stand and utilizing said control means to actuate said ratchet release means and thereby unlock the jack stand.   
     
     
       3. The method of accomplishing a jacking operation by means of hydraulic power while minimizing the problem of hydraulic bleed, comprising the steps of: (a) selecting a system of apparatus including an extendible jack stand with self-locking means, and a hydraulic power unit which is removably attachable to the jack stand in aligned relationship thereto, the power unit also being equipped with control means for unlocking the self-locking means of the jack stand;   (b) placing the jack stand in position to move a load;   (c) attaching the hydraulic power unit to the jack stand;   (d) actuating the hydraulic power unit to extend the jack stand;   (e) when the load has been moved to a desired position and the jack stand is locked, removing the hydraulic power unit; and   (f) subsequently re-attaching the hydraulic power unit to the jack stand and utilizing the control means on the power unit to unlock the jack stand.   
     
     
       4. A method of jacking up and supporting a vehicle or structure, comprising the steps of: selecting a plurality of jack stand units, each being capable of being vertically telescoped to an initial condition, of being vertically extended for raising a load, and of being locked in its vertically extended position;   selecting a machine that is capable of positioning and controlling a jack stand unit;   operating the machine so as to position the plurality of jack stand units, in their initial conditions, in corresponding fixed positions underneath the vehicle or structure;   operating the machine to control the units, one at a time, so that each unit is vertically extended and then locked, so as to raise and support the vehicle or structure; and   when it is desired to lower the vehicle or structure, operating the machine to control the units, one at a time, so that each unit is unlocked and then telescoped to its initial condition;   wherein each jack stand unit is transported, positioned, raised or extended, locked, unlocked, lowered or retracted, and withdrawn under direct control of the machine and without direct application of the hands of an operator to said jack stand.   
     
     
       5. The method of accomplishing a jacking operation by means of hydraulic power while minimizing the problem of hydraulic bleed, comprising the steps of: (a) selecting a system of apparatus including an extendible jack stand with self-locking means, and a hydraulic power unit which is removably attachable to the jack stand in aligned relationship thereto, the power unit also being equipped with control means for unlocking the self-locking means of the jack stand;   (b) placing the jack stand in position to lift a load;   (c) attaching the hydraulic power unit to the jack stand in aligned relationship thereto;   (d) actuating the hydraulic power unit to extend the jack stand and thereby lift the load;   (e) when the load has been lifted to a desired position and the jack stand is locked, detaching and removing the hydraulic power unit;   (f) subsequently re-attaching the hydraulic power unit to the jack stand utilizing the control means on the power unit to unlock the jack stand; and   (g) when the jack stand has been unlocked, utilizing the hydraulic power unit to support the load while the jack stand is being retracted.